The present invention relates to air conditioning units which collect evaporator condensate. More specifically the present invention relates to apparatus in an air conditioning unit for circulating the collected condensate to avoid cold pockets causing condensation on the exterior of the unit.
Air conditioning units such as the so-called self contained air conditioning units commonly used for residential and similar applications, generally include closed refrigeration circuits having an evaporator and a condenser. The unit is normally divided by a partition into an evaporator section and a condenser section, with the evaporator section communicating with the room air to be conditioned and the condenser section communicating with external air such as outdoor air. Refrigerant flows through the refrigeration circuit absorbing heat from the room air at the evaporator and discharging heat to the external air at the condenser. The conventional refrigeration circuit is completed by the addition of a compressor and an expansion device and the appropriate connections between the components.
In the evaporator section air is drawn through the evaporator by the evaporator fan and subsequently discharged into the room. In the evaporator, the refrigerant changes from a liquid state to a gaseous state absorbing heat from the air during the conversion. The temperature of the evaporator during operation is usually below the dew point of the air from which the heat is absorbed. Hence as the air cools, part of the moisture contained as a gas therein condenses into the liquid state and collects on the evaporator surfaces. This condensate is collected by a drain pan under the evaporator and gravity fed through the partition dividing the unit into sections.
In the condenser section, the condensate is disposed of by either draining it to an outside area or by evaporating the condensate at the condenser. The condenser receives hot compressed refrigerant from the compressor and must cool the refrigerant before it passes to the evaporator. A condenser fan is used to circulate air through the condenser for the purpose of absorbing heat. It has, however, been found that if small droplets of condensate are blown against the condenser, the condensate will not only be disposed of by evaporation but the condenser will become more efficient. A slinger such as shown in U.S. Pat. No. 3,766,751 is a device for distributing condensate onto the condenser.
The slinger is often a device mounted to the condenser fan which physically contacts the condensate or creates sufficient eddy currents to lift the condensate into the airstream of the condenser fan to be blown onto the condenser surfaces.
The base pan of the condenser section of the unit forms a reservoir for the collection of condensate.
A condenser fan shroud is usually mounted in the condenser section of the unit to serve as both an air flow guide into the condenser and to further define a path between air entering the unit as well as air being discharged from the unit. This condenser fan shroud also serves to divide the reservoir created in the base pan into two sections.
Previously without other means being provided, cold water draining directly from the evaporator was able to collect in specific areas of the reservoir and would be sufficiently cold to lower the temperature of the exterior of the base pan below the dew point temperature of the adjacent air resulting in condensation being formed on the exterior of the unit.
The present invention provides for sluiceways extending through the condenser fan shroud in communication with the condensate, thereby defining a path in which the condensate may circulate. Air pressure differentials created by the fan when in operation cause the condensate to circulate, mixing the standing warmer condensate with the colder condensate forming on the evaporator and eliminating the cold pockets causing condensation of the exterior of the unit.
Other methods of preventing cold pockets of condensate while effective are more complex and more expensive. For instance, the base pan could be insulated to prevent sweating or a stirring means could be installed for circulation of the collected condensate.